The invention relates to modules for holding and interconnecting data communications cards, and in particular, to an interconnection module for holding and interconnecting optoelectronic cards, and to a method of interconnecting thereof.
When several plug-in optoelectronic cards have to be interconnected according to a required connection scheme, there is a common practice to use a backplane to provide the connection point between the cards. A typical prior art interconnection module 1 is illustrated in FIGS. 1 and 2. A backplane 10, having front and rear sides 12 and 14 respectively, has front side blind mate optical connectors 15 providing connection to the front side of the backplane, and rear side hand inserted optical connectors 18 providing connection to the rear side 14 of the backplane and extending outwardly from the rear surface as shown in FIG. 1. Optical connectors 15 have adaptors 17, which are formed on the front side 12 of the backplane 10 and face outwardly from the front side, and corresponding connector portions 16 carried by optoelectronic cards 22 and inserted in the adaptors 17. Connector portions 16 or the adaptors 17 may optionally have floating features, which allow for required connection tolerances. Each one of the adaptors 15 and connector portions 16 may have one of the connector receptacle and connector plug to mate with each other and to receive the cards 22 as illustrated in FIGS. 1 and 2. The rear side 14 of the backplane 10 provides an interconnect from one card to another card through optical patch cords 26 which have corresponding fiber optic connector portions mating with rear side connectors 18. Alternatively, instead of using patch cords, fiber optic strands may be laminated into the backplane in order to provide connection between the cards (not shown). Products matching these configurations are sold on the open market and represent the current prior art, see, e.g. xe2x80x9cInterconnecting for Networkingxe2x80x9d, Catalog 1307515, issued 9-99, p. 675.
Thus, in order to connect two optoelectronic cards, a fiber optic connector is required on each card as well as on each end of the patch cord. When more than two cards have to be interconnected, it will require multiple optical connectors of different types on both sides of the backplane and a corresponding number of optical patch cords. Use of multiple patch cords results in ineffective utilization of space and makes the design of the interconnection module complicated and expensive. Additionally, the use of patch cords or laminated fiber strands causes substantial optical signal degradation due to the insertion losses through multiple connection points.
Accordingly, there is a need in the industry to develop an alternative interconnection module and method of interconnecting multiple optoelectronic cards which would be less complicated while more flexible and efficient.
Therefore it is an object of the invention to provide an interconnection module and method of interconnecting multiple optoelectronic cards, which would avoid or minimize the above-mentioned problems.
According to one aspect of the invention there is provided an interconnection module, comprising:
a midplane, having a front side and a rear side;
a coupling sleeve formed on the midplane, the sleeve having a front portion and a rear portion extending outwardly from the front side and the rear side of the midplane respectively and providing optical coupling between the front and rear sides of the midplane;
the front and rear portions of the sleeve receiving a front connector and a rear connector respectively so that the connector on each side of the midplane is arranged within the sleeve in one of the first and second positions, wherein in the second position the connector is being rotated approximately by 90 degrees with regard to the first position.
Preferably, the connectors are blind mate optical connectors having floating members to provide required connection tolerances. Depending on system requirements, the connectors may be single fiber connectors or multi-fiber connectors, and each of the front and rear connectors and front and rear portions of the sleeve may have one of the optical receptacle and optical plug selected so as to provide mating between the corresponding connector and portion of the coupling sleeve. Advantageously, the front and rear portions of the sleeve have same shape so that each portion of the sleeve is capable of receiving one of the rear and front connectors, thereby providing that the same connector can be connected on both sides of the midplane. Conveniently, the connectors and the sleeve may have a square or circular cross-section.
Beneficially, the front and rear connectors are carried by front and rear optoelectronic cards arranged on the front and rear sides of the midplane respectively, thereby providing that the cards are arranged on opposite sides of the midplane in one of the two positions, in the first position the front and rear cards being substantially parallel to each other, and in the second position the cards being substantially perpendicular to each other. Generally, a plurality of coupling sleeves may be arranged on the midplane so as to accommodate a plurality of optical connectors carried by optoelectronic cards and to provide connection between N cards on one side of the midplane and M cards on the other side of the midplane. In most practical situations N=1, . . . 20 and M=1, . . . 20. Conveniently, a plurality of coupling sleeves is arranged on the midplane so as to accommodate a plurality of optical connectors carried by N optoelectronic cards on one side of the midplane and M cards on the other side of the midplane and to provide connection between the cards so that each of the N cards on one side of the midplane is connected to a subset of cards on the other side of the midplane, for each of the N cards the number of cards in the subset being variable and less or equal to M in total. If required, the midplane and the cards may carry corresponding electrical connectors.
According to another aspect of the invention there is provided an optical midplane, comprising:
a midplane having a front side and a rear side; and
a coupling sleeve formed on the midplane, the sleeve having a front portion and a rear portion extending outwardly from the front side and the rear side of the midplane respectively and providing optical coupling between the front and rear sides of the midplane;
the front and rear portions of the sleeve being capable of receiving front and rear connectors respectively so that each connector is arranged within the sleeve in one of the first and second positions, wherein in the second position the connector is being rotated by approximately 90 degrees with regard to the first position.
According to yet another aspect of the invention there is provided a combination of a data shelf and a plurality of interconnection modules as described above;
the data shelf having stations provided for receiving and fixing the interconnection modules in the shelf.
According to still yet another aspect of the invention there is provided a method of interconnecting optoelectronic cards, comprising the steps of:
providing a midplane, having a front side and a rear side, and a coupling sleeve formed on the midplane for providing optical coupling between the front and rear sides of the midplane, the sleeve having a front portion and a rear portion extending outwardly from the front side and the rear side of the midplane respectively;
providing front and rear optoelectronic cards carrying front and rear optical connectors respectively;
inserting front and rear connectors into the front and rear portions of the sleeve respectively so that the connector on each side of the midplane is arranged within the sleeve in one of the first and second positions, wherein in the second position the connector is being rotated approximately by 90 degrees with regard to the first position;
thereby providing that the cards are interconnected and arranged in one of the two positions, in the first position the front and rear cards being substantially parallel to each other, and in the second position the cards being substantially perpendicular to each other.
According to one more aspect of the invention there is provided an interconnection module, comprising:
a combined midplane having a midplane section and a backplane section;
the midplane section having a front side and a rear side, and a coupling sleeve formed on the midplane section, the sleeve providing optical coupling between the front side and rear side of the midplane section and having a front portion and a rear portion extending outwardly from the front side and the rear side of the midplane section respectively;
the front and rear portions of the sleeve being capable of receiving front and rear connectors respectively so that the connector on each side of the midplane is arranged within the sleeve in one of the first and second positions, wherein in the second position the connector is being rotated by approximately 90 degrees with regard to the first position, thereby providing connection between different sides of the midplane section;
the backplane section being formed as an extension of the midplane section to form the combined midplane; and
the backplane section having corresponding backplane adaptors for receiving backplane connectors to provide connection between the same side of the backplane section.
Conveniently, the backplane section is formed so as to be substantially in a plane of the midplane section. Alternatively, it may be formed so as to be substantially perpendicular to the midplane section. Preferably, the midplane and backplane sections are formed as integral parts of the combined midplane.
The interconnection modules as described in the embodiments of the invention provide the following advantages. They reduce the accumulation of optical signal degradation due to insertion loss through multiple connection points, and provide a cost advantage by reducing the total number of the optical connectors. Additionally, the modules provide flexible system architecture which allows required interconnection between the cards on opposite and same sides of the midplane. Such flexibility becomes extremely important for optical cards carrying optical switches, splitters and other components, which require multiple interconnects.